III. Form
Foundational Concepts for Phrase-Level Forms
John Peterson
Key Takeaways
This chapter describes the hierarchy of musical form, motives, and segmentation analysis.
- Musical form can be understood as a hierarchical grouping of units.
- The smallest of these groupings is a motive, which is a regularly recurring unit of music that’s typically smaller than an idea. In an analysis, we circle and label motives that recur and are transformed across a work. Avoid identifying large melodies or portions of melodies as motives—motives are short!
- A segmentation analysis is a way to show the grouping units of a passage or whole piece. To do a segmentation analysis, we begin by identifying phrase endings, which are often marked by cadences. Then, we divide phrases into smaller units using square brackets above the score to show the idea level.
Hierarchy
One way to understand musical form is as a hierarchical grouping of units. shows that a piece contains movements, movements contain sections, sections contain themes, themes contain phrases, and so on.
Although the diagram in
looks quite simple, the relationships between the levels are a little more complicated in reality. For instance, sometimes two levels are collapsed into one: a single phrase may comprise an entire section of a work, so it may not always be worthwhile to distinguish between each level. It’s best to think of as a guide and not as something that strictly defines formal levels.This chapter, along with the three that follow it, are focused on phrase-level form, or the various ways in which a phrase may be constructed of motives, ideas, and sometimes subphrases (which will be discussed in later chapters).
It’s a regularly recurring unit of music that’s typically smaller than an idea (the focus of the next section of this chapter). Each video in discusses a motive from a different work. They all contain the same basic information, so you might choose to watch the one that interests you the most, or you might watch all three.
While a motive does not necessarily have to repeat, those that do are usually the most interesting ones to talk about, so we tend to focus on motives that recur throughout a passage.
There are many kinds of motives (e.g., rhythmic, pitch, contour, timbre), but the word “motive” by itself most often refers to a pitch-based motive. A motive that’s primarily recognizable from its rhythmic design, for example, would be spoken of as a “rhythmic motive.”
As a motive recurs throughout a work, it tends to change. Some common transformations are:
- Enlargement: making the durations of a motive longer than the original
- Contraction: making the durations of a motive shorter than the original
- Inversion: changing the direction of the motive (e.g., instead of going up, it goes down)
- Displacement: changing the metric position of the motive relative to its original statement
- Retrograde: stating the motive backward in comparison to the initial statement
- Intervallic manip